<!DOCTYPE html>
<style>
div {
 width:100px;
 height:600px;
 margin:5px 0 0 5px;
 font-size: 30px;
 float:left;
}
div#one {
 line-height: calc(300%);
}
div#two {
 line-height: calc(100px);
}
div#three {
 line-height: calc(20px + 300%); 
}
div#four {
 line-height: calc(10px * 2);
}
div#five {
 line-height: calc(50% - 3px);
}
div#six {
 line-height: calc(25% - 3px + 25%);
}
div#seven {
 line-height: calc(25% - 3px + 12.5% * 2);
}
div#eight {
 line-height: calc(25% - 3px + 12.5%*2);
}
div#nine {
 line-height: calc(25% - 3px + 2 * 12.5%);
}
div#nine {
 line-height: calc(25% - 3px + 2*12.5%);
}
div#ten {
 line-height: calc(25% - 3px + 2 * 12.5%);
}
div#div-11 {
 line-height: calc(30% + 20%);
}
div#div-12 {
 line-height: calc(3 * 2 + 3 / 6);
}
</style>
<div id="one">line height is 300%</div>
<div id="two">line height is 100px</div>
<div id="three">line height is 50px</div>
<div id="four">line height is 10px * 2</div>
<div id="five">line height is 50% - 3px</div>
<div id="six">line height is 25% - 3px + 25%</div>
<div id="seven">line height is 25% - 3px + 12.5% * 2</div>
<div id="eight">line height is 25% - 3px + 12.5%*2</div>
<div id="nine">line height is 25% - 3px + 2*12.5%</div>
<div id="ten">line height is 25% - 3px + 2 * 12.5%</div>
<div id="div-11">line height is 30% + 20%</div>
<div id="div-12">line height is 3 * 2 + 3 / 6</div>
</html>
